Saidou et al. J. Appl. Biosci. 2014. Effet de l'urée et du NPK perlés et super granulés sur la productivité des variétés de riz IR841 et NERICA-L14 au Sud-Bénin 6575 Effet de l'urée et du NPK 15-15-15 perlés et super granulés sur la productivité des variétés de riz IR841 et NERICA-L14 en zone de bas-fond au Sud-Bénin

Effect of pearl and super granule urea and NPK 15-15-15 on the productivity of IR841 and NERICA-L14 rice varieties in the inland valley of southern Benin Objectives: The study was carried out on the site of Koussin and Lélé in the southern Benin, exploring the efficiency of the supply of the pearl and super granule urea (46%) and NPK 15-15-15 for rice production in the inland valley. Specifically, the study aims to assess the effect of the different forms of urea and NPK 15-15-15 on the growth and yield parameters of two inland rice varieties (IR841 and NERICA-L14) widely adopted in cultivated lowland of Benin. Methodology and results:The experimental design is a split-plot with two rice varieties, four forms of fertilizer (pearl urea + NPK; pearl urea + super granule NPK; super granule urea + pearl NPK and super granule urea + super granule NPK) in four replications. The growth and yield parameters were assessed. Super granule urea + super granule NPK and super granule urea + pearl NPK have significantly (P < 0.0001) induced higher plant height, numbers of tiller and rice grain per panicle compared with the other treatments whatever the rice variety. However, mean yields of paddy rice and straw were significantly higher (P < 0,0001) for super granule urea + super granule NPK (paddy rice yield : 5,52 ± 0,26 t/ha ; straw yield : 12,19 ± 0,54 t/ha) and super granule urea + pearl NPK (paddy rice yield: 4,82 ± 0,22 t/ha ; straw yield : 10,79 ± 0,61 t/ha). In general with these treatments, the highest yields were recorded with IR841 rice variety. Conclusion and application:The super granule fertilizers are recommended for improving rice production in the inland valley as they improve substantially the yields. In order to improve the efficiency of these fertilizers especially the sources of nitrogen, the study suggests to supply urea super granule + NPK super granule or urea super granule + pearl NPK to improve growth and yields parameter of IR841 rice variety.